Gmail has this feature where appending a plus ("+") sign or a dot to an email address will still have it sent to the same address. This makes it easier to filter emails sent to you, by checking which email address the email was sent to and then label, star or auto-delete emails based on that.

Yahoo! mail also has a similar feature: Address Guard, which uses the dash ("-") sign.

Does Hotmail or Outlook.com have a similar feature? If yes, how does it work?

Outlook.com allows the creation of email aliases, which is essentially the same as the Gmail and Yahoo features that you mention. Email sent to your aliases will forward to your regular Outlook.com account.

Outlook.com does have limits, though: you can only create up to 5 aliases per year, and you can have a maximum of 15 aliases in total.

This is hardly the same thing as gmail plus addressing. With gmail and other services (I use SmarterMail on my dedicated server), I can write for example info+stackexchange@domain.com and essentially provide unique emails for each service I sugnup for. With outlook alias I would have to manually create an alias (and there's a maximum limit) so this is not even comparable.
–
smartinsSep 14 '13 at 14:54